[Study of factors requiring more than two ESWL treatments]

Nine hundred and fifty cases with renal and ureteral stones were treated by extracorporeal shock wave lithotripsy (ESWL) with Siements Lithostar unit from September, 1988 to October, 1990 at Kinki University Hospital. ESWL treatments were performed twice or more on 110 cases (DIFFICULTY GROUP). Ninety-seven cases who were cured by only one ESWL treatment were selected randomly as the control group. The two groups were retrospectively compared to study the factors requiring more than two times of ESWL treatments. There was a significant difference in the time of spontaneous stone discharge before ESWL treatment, the degree of hydronephrosis and the incidence of staghorn calculi as well as middle-lower ureteral calculi between the two groups. There was not a significant difference but a tendency to a longer period of stone existing at the same position and a higher percentage of past history of percutaneous nephrolithotropsy (PNL) in DIFFICULTY GROUP. Because ESWL monotherapy is considered to have limitations, auxiliary procedures or other treatments such as PNL and transurethral lithotripsy are recommended for patients in who in the stones were poorly disintegrated by the first ESWL treatment.